Waterloo climate

Waterloo Weather in May

NOAA 1991-2020 normals for Valley NWS, 7.7 km from Waterloo

Average highs run from 67°F on May 1 to 79°F on May 31, and lows from 47°F to 59°F. Normal precipitation for the month is 4.74 in over about 13 wet days.

May day by day

The normal high and low for each date, and the record, in °F.

Normal daily high and low temperature at Waterloo, in °F, with the record for each date.20406080100151015202530
  • Normal low
  • Normal high
  • Record high
  • Record low

May at a glance

Average high
73°F
Average low
53°F
Precipitation
4.74 in
Snowfall
0.1 in
Record high
98°FMay 15, 2013
Record low
31°FMay 3, 2011
Chance of a freeze
6%
Days of 90°F or more
1.0
Daylight
14 h 01 min to 14 h 56 min
Cloud cover
64%
Humidity
70%
Dew point
51°F
Wind
11.6 mph

Every day of the month

A wet day has at least 0.01 inch of precipitation; snow means at least 0.1 inch of snowfall.

DateNormal highNormal lowRecord highRecord lowChance wetChance of snow
May 167°F47°F85°F 200732°F 200540%1%
May 268°F47°F86°F 202133°F 200540%1%
May 368°F48°F82°F 201231°F 201140%1%
May 468°F48°F84°F 201231°F 201141%1%
May 569°F48°F88°F 201236°F 201341%1%
May 669°F49°F91°F 201238°F 202141%1%
May 769°F49°F85°F 201640°F 202141%0%
May 870°F50°F95°F 201438°F 201041%0%
May 970°F50°F91°F 201738°F 201041%0%
May 1071°F51°F97°F 201139°F 201941%0%
May 1171°F51°F96°F 201137°F 200841%0%
May 1271°F51°F91°F 202237°F 201341%0%
May 1372°F52°F94°F 202237°F 201341%0%
May 1472°F52°F87°F 200737°F 201641%0%
May 1573°F53°F98°F 201337°F 201441%0%
May 1673°F53°F91°F 201734°F 201441%0%
May 1773°F54°F93°F 201935°F 201441%0%
May 1874°F54°F88°F 201239°F 201441%0%
May 1974°F55°F88°F 201238°F 201541%0%
May 2075°F55°F91°F 200639°F 201541%0%
May 2175°F55°F86°F 200939°F 201541%0%
May 2275°F56°F85°F 200536°F 202241%0%
May 2376°F56°F87°F 201046°F 201941%0%
May 2476°F57°F91°F 201247°F 201741%0%
May 2576°F57°F90°F 201846°F 200741%0%
May 2677°F57°F94°F 201846°F 201141%0%
May 2777°F58°F97°F 201846°F 201141%0%
May 2878°F58°F98°F 201842°F 202241%0%
May 2978°F59°F94°F 201844°F 202141%0%
May 3078°F59°F88°F 201046°F 200541%0%
May 3179°F59°F91°F 202346°F 201540%0%

Chance of rain

The chance of at least 0.01 inch of precipitation on each date at Waterloo, in percent, and of at least 0.1 inch of snowfall.010203040501102030
  • Chance of a wet day
  • Chance of snowfall

Sunrise and sunset

Times for 2026, local time (CDT).

May 1
sunrise 6:22 AM, sunset 8:23 PM
May 31
sunrise 5:55 AM, sunset 8:51 PM

Every day of May: sun and moon

Other months

Sources

Normals: NOAA NCEI U.S. Climate Normals, 1991-2020, station USC00258795 (Valley NWS), public domain. Records: NOAA GHCN-Daily, station USC00253467, every year on file, quality-flagged values removed. Cloud, humidity, wind and sunshine: NASA POWER (MERRA-2, CERES and GEWEX SRB), 1991-2020. The data was obtained from the National Aeronautics and Space Administration (NASA) Langley Research Center's Prediction Of Worldwide Energy Resources (POWER) project funded through the NASA Earth Science Division: POWER Daily API v2, accessed 2026-09-24. Sun and moon: computed with the NOAA solar equations and Meeus.